XRF 241001A/SN 2024aiiq: A Faint Soft X-ray Transient Detected by SVOM with a Broad-Line Type Ic Supernova Revealed by JWST

@article{schneider2026241001asn,
  title = {{XRF 241001A/SN 2024aiiq: A Faint Soft X-ray Transient Detected by SVOM with a Broad-Line Type Ic Supernova Revealed by JWST}},
  author = {B Schneider and M Brunet and B.P Gompertz and D Turpin and D.B Malesani and O Godet and A.J Levan and F Daigne and N Sarin and N.A Rakotondrainibe and A Martin-Carrillo and J.T Palmerio and C.C Thöne and H.L Li and A Saccardi and A de Ugarte Postigo and S Antier and V Buat and D Ďurovčíková and L Izzo and J.K Leung and G Mo and Y.L Qiu and S.D Vergani and J Wang and J.Y Wei and L.P Xin and R Mochkovitch and B Zhang and H.B Cai and S Campana and A Coleiro and B Cordier and P d'Avanzo and N Dagoneau and V d'Elia and Y.W Dong and D Götz and S Guillot and X.H Han and D.H Hartmann and L Huang and Y.F Huang and P Jakobsson and A Klotz and C Lachaud and X.M Lu and P Maggi and M de Pasquale and F Piron and R Salvaterra and S Schanne and J Sollerman and N.R Tanvir and Z Vidadi and P Wang and C Wu and S.L Xiong and Y Xu and T Zafar},
  journal = {Astronomy \& Astrophysics - A\&A},
  year = {2026},
  month = nov,
  doi = {10.1051/0004-6361/202660544},
  eprint = {2604.20346},
  archivePrefix = {arXiv},
  url = {https://hal.science/hal-05614088v1},
  note = {CC BY 4.0},
}

TY  - JOUR
TI  - XRF 241001A/SN 2024aiiq: A Faint Soft X-ray Transient Detected by SVOM with a Broad-Line Type Ic Supernova Revealed by JWST
AU  - B Schneider
AU  - M Brunet
AU  - B.P Gompertz
AU  - D Turpin
AU  - D.B Malesani
AU  - O Godet
AU  - A.J Levan
AU  - F Daigne
AU  - N Sarin
AU  - N.A Rakotondrainibe
AU  - A Martin-Carrillo
AU  - J.T Palmerio
AU  - C.C Thöne
AU  - H.L Li
AU  - A Saccardi
AU  - A de Ugarte Postigo
AU  - S Antier
AU  - V Buat
AU  - D Ďurovčíková
AU  - L Izzo
AU  - J.K Leung
AU  - G Mo
AU  - Y.L Qiu
AU  - S.D Vergani
AU  - J Wang
AU  - J.Y Wei
AU  - L.P Xin
AU  - R Mochkovitch
AU  - B Zhang
AU  - H.B Cai
AU  - S Campana
AU  - A Coleiro
AU  - B Cordier
AU  - P d'Avanzo
AU  - N Dagoneau
AU  - V d'Elia
AU  - Y.W Dong
AU  - D Götz
AU  - S Guillot
AU  - X.H Han
AU  - D.H Hartmann
AU  - L Huang
AU  - Y.F Huang
AU  - P Jakobsson
AU  - A Klotz
AU  - C Lachaud
AU  - X.M Lu
AU  - P Maggi
AU  - M de Pasquale
AU  - F Piron
AU  - R Salvaterra
AU  - S Schanne
AU  - J Sollerman
AU  - N.R Tanvir
AU  - Z Vidadi
AU  - P Wang
AU  - C Wu
AU  - S.L Xiong
AU  - Y Xu
AU  - T Zafar
PY  - 2026
DA  - 2026/11/05
JO  - Astronomy & Astrophysics - A&A
DO  - 10.1051/0004-6361/202660544
UR  - https://hal.science/hal-05614088v1
AB  - X-ray flashes (XRFs) are a type of gamma-ray bursts (GRBs) with prompt emission predominantly below 30 keV poorly detected by previous missions. The advent of the SVOM mission, with its wide-field instrument ECLAIRs, provides a new way to detect soft X-ray transients such as XRFs. We present photometric and spectroscopic observations of XRF 241001A detected by SVOM, a soft, sub-luminous, and low-energetic burst located in a poorly populated region of the Amati relation. We investigate the origin of its faint, soft high-energy emission to assess its connection to the long GRB population. We analyze the SVOM/ECLAIRs prompt emission and model its afterglow emission from X-ray to-radio. We present JWST/NIRSpec and SVOM/VT observations of the associated supernova (SN 2024aiiq), which we model with an Arnett radioactive decay component and compare its properties with previously detected GRB/SNe. XRF 241001A is located at z = 0.573 and has a prompt emission dominated by photons below 20 keV with a duration of T90 = 3.14 seconds. Its spectrum can be modeled by non-thermal or thermal models, all pointing towards a low Epeak < 10 keV and Eiso ~ 8x10^49 erg. The X-ray-to-radio afterglow modeling favors an origin from a relativistic jet viewed on-axis. In the optical, XRF 241001A exhibits an early blue emission, similar to that detected in some fast X-ray transients and inconsistent with synchrotron emission. The JWST/NIRSpec observations firmly established its collapsar origin by revealing a SN Type Ic with broad lines, comparable to SN 1998bw and SN 2025kg-like events. XRF 241001A is a soft, low-luminosity collapsar event produced by a weak relativistic jet observed on-axis, supporting the view that part of the XRF population forms the low-energy tail of the long GRB population. It demonstrates the potential of SVOM/ECLAIRs to probe the soft regime of the high-energy transient population.
SN  - 0004-6361
SN  - 1432-0746
ER  -